A vehicle may typically include a climate control system which maintains a temperature within a passenger compartment of the vehicle at a comfortable level by providing heating, cooling, and ventilation. Comfort may be maintained in the passenger compartment by an integrated system referred to as a heating, ventilating and air conditioning (HVAC) air-handling system. The HVAC air-handling system conditions air flowing therethrough and distributes the conditioned air throughout the passenger compartment.
The design of an HVAC air-handling system includes features that control air flow volume, air temperature, and air flow paths, for example. Performance of the HVAC air-handling system may be designed to comply with particular targets including temperature stratification, wherein stratification is the temperature difference between various outlets of the HVAC air-handling system. For some operating states it may be desirable to manipulate hot air streams and cold air streams to produce a stratification between outlets. For other operating states no stratification is desired. The level of desired stratification may fluctuate and design features may allow stratification to be adjustable.
To comply with the desired stratification targets, HVAC air-handling systems may include features including baffles, conduits, mixing plates, and/or doors to facilitate mixing of hot air streams with cold air streams. The addition of these features and/or components can reduce airflow, degrade flow efficiency, increase noise, and increase the cost and weight of the system. Further, many of the prior art systems fail to meet the desired stratification targets.
In certain systems, adjustable HVAC doors seal against mating sealing surfaces to position the HVAC doors and to facilitate mixing of hot air streams with cold air streams. Known adjustable HVAC doors seal against mating sealing surfaces in one single variable stage as the door closes. As a non-limiting example, as a rotationally actuated door rotates from an open position to a closed position, it first seals against sealing surfaces closest to the centerline of rotation of the door, and then lastly seals against sealing surfaces furthest from the centerline of rotation of the door. Similarly, as a rotationally actuated door rotates from a closed position to an open position, the door seal pulls away along multiple surfaces (e.g., as many as three or six surfaces) all at one time, releasing a proportionally high volume of air flow all at one time, especially along the surfaces furthest from the centerline of rotation of the door. This high volume release of airflow can create problems with temperature linearity control, airflow bleed, and distribution control.
To control the volume of airflow release, small gaps can be provided to shade walls adjacent to the door (or variable gaps that reduce to 0 mm). While this can be an effective way to control the amount of airflow volume that flows past the door, it can be susceptible to unwanted noise, vibration, and harshness (NVH) (e.g., scraping, squeaking, hooting, whistles, etc.) and door binding. Accordingly, improvements in ways of opening, closing, and sealing HVAC doors are desirable to optimize HVAC air-handing system operation, wherein a cost and a weight of the system are minimized, and airflow, noise, flow efficiency and stratification of the system are optimized.